Listen to Robert Emmerich introduce "The Big Apple," a hit song from 1937. Music written by Bob and performed by Tommy Dorsey's Clambake Seven with Bob on piano. Lyrics written by Buddy Bernier and sung by Edythe Wright. Audio provided by Dorothy Emmerich.

"The darkest hour has only sixty minutes” is a popular inspirational saying. “Yes, it is true that the darkest hour is only sixty minutes, after all” was cited in 1897. “Don’t forget that the darkest hour is only sixty minutes” was cited in 1898.

The Contrary Opinion—ButtonsThe Darkest Hour Has Only Sixty Minutes
Morris MandelBy Morris Mandel, an American Jewish educator, this button reminds us that troubles pass. As an investor, trouble for you may be a big bear market or a tiny news items that causes your stock to crater. Your job is to look beyond the trouble, remember that good times lie ahead, and take the actions to position yourself to benefit from them.

Google Books
27 October 1897, THe Insurance Press, pg. 4, col. 4:
POINTERS FOR UNINSURED.
(...)
Yes, it is true that the darkest hour is only sixty minutes, after all.